Dibenzylidene sorbitol (also called dibenzaldehyde monosorbitol acetal, or dibenzyl monosorbitol acetal or dibenzylidene monosorbitol acetal) and derivatives thereof such as those which are substituted on one or both of the aromatic rings with a fluorine or methoxy group and those which have the sorbitol portion replaced with other reduced sugars such as xylitol or ribitol as described in U.S. Pat. No. 5,609,855 assigned to Procter & Gamble (collectively referred to as dibenzylidene sorbitol or "DBS") may be used in various food and cosmetic applications. For cosmetic uses the more interesting ones are those focused on obtaining a translucent or clear product. While dibenzylidene sorbitol is stable in alkaline or neutral media, such compounds are not stable in acidic media. In an acidic environment, such as in the presence of acidic antiperspirant materials, and when in the presence of even small amounts of water, the dibenzylidene sorbitol deteriorates and breaks down. Also, the use of DBS sometimes causes problems in the aesthetics of cosmetic products or problems with structural properties. Accordingly, there is a need to find a way to form products containing DBS which are stable and which have acceptable aesthetics.
The use of DBS requires the use of polyhydric alcohols such as propylene glycol as a solvent if a clear, transparent product is desired. The high propylene glycol content, when combined with aluminum salts which are included in antiperspirant compositions for wetness control, contribute to undesirable tackiness or a sticky feel for these products when applied to the axilla region of the body. DBS clear antiperspirant sticks were first formulated in the late 1970's. There have been continued technical efforts to reduce the negative sensory attributes. Some of these efforts have focused on alternative solvents to replace a portion of the propylene glycol with organic esters known in the art as emollients. This creates a further problem since many of these emollients are either unsafe for personal care products or do not achieve acceptable aesthetics.
For formulating personal care products the incorporation of silicone fluids is known in the art. Silicone fluids such as cyclosiloxanes (for example, DOW CORNING.RTM. 244 and 245 Fluids) are used in some major commercial products. Silicone fluids are used because of their low tackiness, superior glide and skin-feel properties. However, silicone fluids are difficult to introduce into DBS based cosmetic stick products such as antiperspirants because they are not good solvents for DBS and they are not readily compatible with propylene glycol and many organic esters or emollients.
Sonic of the efforts on each of these fronts are described as follows. For example, some efforts have focused on the stability of DBS. United Kingdom Patent GB 2 280 111 assigned to Union Camp Corporation, describes a gel stick composition comprising a dihydric alcohol as a primary solvent, a co-solvent such as low molecular weight polyethylene glycol, water and/or glycerine, a buffering agent and DBS as a gelling agent.
U.S. Pat. No. 4,720,381 to Schamper et al notes stability problems with this approach and itself describes the use of solvents having less reactive hydroxy groups or alcohols with selected chain lengths in a DBS composition.
U.S. Pat. No. 4,816,261 to Luebbe et al describes stable deodorant gel stick compositions comprising DBS with a polar solvent and a coupling agent such as polypropylene glycol ethers of fatty alcohols.
U.S. Pat. No. 4,822,602 to Sabatelli teaches the use of dimethicone copolyols and volatile silicones in clear DBS-based sticks.
PCT publication WO 96/26709 assigned to Gillette describes clear DBS-based antiperspirant sticks with hydroxypropyl cellulose, dimethicone copolyol and EDTA.
U.S. Pat. No. 5,405,605 to Shin teaches anhydrous clear antiperspirant sticks substantially free of lower monohydroxy alcohols and which contain dibenzilidene monosorbitol with weak basic organic nitrogen containing compounds as a stabilizing agent.
U.S. Pat. No. 4,518,582 to Schamper, et al discloses an antiperspirant stick composition containing dibenzyl monosorbitol acetal in the presence of acidic antiperspirant-active salts, which composition is stable for extended periods of time at elevated temperatures. The composition contains at least a reactive solvent (such as water, methanol, ethanol, n-propanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, etc.), dibenzyl monosorbitol acetal, an antiperspirant-active compound, and a gel stabilizer such as magnesium sulfate, zinc acetate and mixtures thereof. This patent discloses that the stabilizer prevents or retards deterioration of the gelled sticks, especially when exposed to elevated temperatures.
Another patent disclosing stabilizers for solid gel antiperspirant sticks containing an acidic antiperspirant-active compound in the presence of dibenzyl monosorbitol acetal is U.S. Pat. No. 4,719,102 to Randhawa, et al. This patent discloses that the sticks include a solvent which is a small, polar organic compound such as cyclic esters, amides, amines, ketones, ureas, carbamates, sulfoxides and sulfones, and their open chain analogs; a cosolvent such as primary or low molecular weight alcohols and/or glycols; dibenzyl monosorbitol acetal; an antiperspirant-active compound; and a gel stabilizer such as N-(2-hydroxyethyl) fatty (C.sub.8 -C.sub.20) acid amides, magnesium sulfate, zinc acetate, acetamide monoethanol amine and hexamethylenetetramine, and mixtures thereof.
U.S. Pat. No. 4,722,835 to Schamper, et al also discloses antiperspirant gel stick compositions gelled with dibenzyl monosorbitol acetal and containing an acidic antiperspirant compound, and also containing a stabilizer for the gel. This patent teaches that the compositions include a solvent which is a small, polar organic compound, as discussed previously in connection with U.S. Pat. No. 4,719,102; dibenzyl monosorbitol acetal; an antiperspirant-active compound; and a gel stabilizer such as zinc oxide, calcium acetate, magnesium oxide, calcium carbonate, calcium hydroxide, magnesium carbonate, sodium carbonate, zinc carbonate and potassium carbonate. This patent discloses that these basic metallic salt gel stabilizers can stabilize the gel, even at high temperatures.
U.S. Pat. No. 5,490,979 to Kasat et al describes a clear DBS stick comprising guanidine carbonate as the buffer and which is made by a unique processing method.
Other patent documents also disclose antiperspirant sticks gelled with a dibenzylidene sorbitol and include stabilizers for the gel.
EP Application No. 451,002 A2 discloses a stable, substantially anhydrous and substantially lower monohydric alcohol free, transparent, gelled, antiperspirant composition gelled by dibenzylidene monosorbitol acetal, containing acidic antiperspirants, and utilizing dihydric alcohols containing 3 to 6 carbon atoms as solvents, with the acetal being stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected organic base, the organic base being a weakly basic, nitrogen-containing, organic compound.
EP Application No. 512,770 A1 discloses a stable, substantially anhydrous and substantially lower aliphatic monohydroxy alcohol free cosmetic composition gelled by dibenzylidene monosorbitol acetal, and containing acidic antiperspirant compounds and utilizing dihydroxy aliphatic alcohols containing 3-6 carbon atoms as solvents, wherein the dibenzylidene monosorbitol acetal gelling agent is stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected inorganic base, the inorganic base including alkali and alkaline earth metal oxides, hydroxides, carbonates or bicarbonates, and trivalent metallic hydroxides.
PCT No. WO92/19221 discloses solid antiperspirant compositions in gel stick form, having an acid pH, and including (1) an antiperspirant active; (2) a gelling agent selected from the group consisting of substituted and unsubstituted dibenzylidene alditols; (3) a solvent for the gelling agent, preferably including a solvent material selected from the group consisting of monohydric and polyhydric alcohols, and mixtures thereof; and (4) a gelling agent stabilizer, the stabilizer being a basic metallic salt of an acid having a pKa of from about 3.8 to about 6.5 at 25 degrees C., the salt being at least partially soluble in the composition and being selected from the group consisting of C.sub.4 -C.sub.6 dicarboxylate salts, C.sub.6 -C.sub.8 monocarboxylate salts, and substituted or unsubstituted benzoate salts, and mixtures thereof, the gelling agent stabilizer not containing amino or amido functionalities. This patent document teaches that for clear or translucent sticks, the gelling agent stabilizer present in the composition should be fully soluble in the composition, in order to minimize refraction of light.
The foregoing patent documents also disclose methods for forming the disclosed antiperspirant stick compositions containing the antiperspirant materials and gelling agent. In particular, attention is directed to U.S. Pat. Nos. 4,719,102 and 4,722,835. Each of these patents discloses processes of forming the stick compositions, including dissolving the antiperspirant active in one phase and the dibenzyl monosorbitol acetal gellant in another phase. The two phases are then combined and poured into a mold or into the final package. The other components are added to either of the two phases depending on the compatibility of the component with the phases. More phases can be utilized, if desired, by forming a separate solution of some of the components, with the separate phases then being added to either of the two main phases; or all of the phases could be poured together at the end, as, for example, with a multi-stream filling head or an in-line mixer.
PCT No. WO92/19221 discloses a process of forming an antiperspirant gel stick, including preparing a solution containing the gelling agent, a solvent for the gelling agent, and the gelling agent stabilizer; mixing an antiperspirant active into such solution; and cooling the solution to form a gel.
There have also been efforts to develop DBS compositions to improve the aesthetics and/or mechanical properties while not sacrificing stability.
U.S. Pat. No. 4,346,097 to Roehl discloses a solid translucent gelled antiperspirant composition comprising DBS with an oleaginous compound (such as selected siloxanes, selected esters with an aliphatic character and branched chain hydrocarbons) to reduce stickiness.
PCT Publication Number 96/26709 to Vu et al describes a clear gel cosmetic stick which includes a liquid vehicle, an antiperspirant salt dissolved in the liquid vehicle, DBS and one or both of hydroxypropyl cellulose and a chelating agent. The hydroxypropyl cellulose maintains the hardness of the stick.
U.S. Pat. No. 4, 863,72 1 to Beck et al describes the use of particulate cellulose ether polymers such as hydroxyethyl cellulose in antiperspirant compositions which are substantially free of polar solvents.
European Patent 0 260 030 B1 assigned to Unilever N.V. describes a transparent deodorant stick containing DBS and a thickening agent such as a chemically modified cellulose, polyacrylic acid, and/or polyacrylic acid copolymers and mixtures of the foregoing.
Other references of interest include U.S. Pat. No. 4,472,835 to Schamper et al; Zombeck, A., "Novel Formulations Based on Nonaqueous Emulsions of Polyols in Silicones" (Paper presented at the 19th IFSCC Congress, Sydney, Oct. 22-25, 1996); and Schamper, T., et al, "Acid Stable Dibenzylidene Sorbitol Gelled Clear Antiperspirant Systems", J. Soc. Cosmet. Chem., Vol. 37, pages 225-231 (July/August 1986); Smith, J. M., et al, J. Mater. Chem., 5(11): 1899-1903 (1995).
There continue to be efforts to formulate improved cosmetic compositions especially sticks which have translucent to clear appearance and which have aesthetically acceptable properties. U.S. Pat. No. 5,500,209 to Ross et al describes a gel or stick composition for reduction of body malodor using a polyamide gelling agent. This composition is stated to have good stability and to be able to provide a clear antiperspirant or deodorant product with good structural integrity.
U.S. Pat. No. 5,603,925 to Ross et al teaches the use of a polyamide gelling agent in an antiperspirant product. The composition uses a glycol-free solvent system to reduce the problems of tack and achieve more acceptable properties.
U.S. Pat. No. 4,440,742 to Marchner discloses a stable cosmetic stick deodorant without the use of bacteriostats and comprising a polyhydric alcohol (such as propylene glycol) solidified by a fatty acid soap and containing from 0.1-70% alkali metal bicarbonate.
U.S. Pat. No. 4,822,602 to Sabatelli describes cosmetic compositions such as deodorant and antiperspirant sticks comprising (a) water-soluble active; (b) dimethicone copolyol; (c) volatile silicone oil; (d) propylene glycol; (e) C2-C4 monohydric alcohol; (f) water; (g) solidifying agent (such as soap type gel forming agents and DBS); and (h) coupling agent (such as C6-C22 fatty alcohols and propylene glycol ethers of C4-C22 fatty alcohols).
U.S. Pat. No. 4,725,430 teaches a clear or translucent cosmetic stick containing an acidic material (such as antiperspirant salts) and a reactive solvent (for example, various propylene glycols) using DBS as the gelling agent and an N-(2-hydroxyethyl) acetamide as the stabilizing agent.
U.S. Pat. No. 5,302,382 to Kasprzak describes a method of making stable emulsified personal care products which includes the steps of (i) forming an anhydrous silicone mixture having a silicone oil or silicone gum with two silicone oxyalkylene copolymers; (ii) forming an aqueous based pre-emulsified personal care product; and (iii) adding the anhydrous silicone mixture directly to the pre-emulsified personal care product without further emulsification.
U.S. Pat. No. 5,449,519 to Wolf et al describes a cosmetically acceptable composition with keratolytic activity which composition includes a carrier molecule having at least one hydroxyl or amino group.
U.S. Pat. No. 5,531,986 to Shevade et al describes a low residue antiperspirant solid stick containing an antiperspirant active, volatile and nonvolatile silicone materials, dimethicone copolyol and high-melting point and low-melting point waxes.
There still remains a need, however, to develop translucent, preferably clear, cosmetic products which provide reduced tack in a DBS product. Thus, it is an object of the present invention to provide a cosmetic composition which comprises DBS and which provides reduced tack when applied to the skin. It is a further object of the invention to provide cosmetic compositions containing DBS which can be used to form deodorant and/or antiperspirants which are translucent to clear. It is yet another object of the invention to provide cosmetic compositions which enhance the compatibility of DBS in propylene glycol systems which also contain silicone fluids. These and other objects of the invention will be apparent from the following description of the invention.